/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.curator.x.discovery.details;

import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.x.discovery.ServiceInstance;

/**
 * Listener for changes to a getGroup cache
 */
public interface ServiceCacheListener<T> extends ConnectionStateListener {
    /**
     * Called when the cache has changed (instances added/deleted, etc.)
     */
    void cacheChanged();

    /**
     * Added by happyyangyuan.
     * 扩展的服务缓存监听器
     *
     * @param event    事件
     * @param instance 服务实例
     */
    default void cacheChanged(PathChildrenCacheEvent event, ServiceInstance<T> instance) {
        //nothing to do. 向下兼容
    }
}
